Intercropping and weed management effect on soil microbial activities in newly planted mango and citrus orchards

Application of herbicides and other agro-chemicals used in agriculture affects the vital functions and population dynamics of soil microorganisms. Soil microbial population was assessed in 30 days interval up to 90 days in mango and citrus orchards. Among the treatments, intercropping of greengram-pea- greengram recorded higher bacterial population (21.7 × 10⁶cfu/g), was followed by intercropping of cowpea-pea-cowpea (19.5x10⁶ cfu/g) at 90 days after spraying. It was found that the highest fungi population was recorded in intercropping of greengram-pea-greengram combined with herbicide application treatment (14.4 × 10³ cfu/g). Similarly, higher actinomycetes population was observed in intercropping of greengram-pea-greengram treatment (8.2 × 10³cfu/g) followed by intercropping of cowpea-pea-cowpea (7.3 × 10³cfu/g) in mango orchard. In citrus field, highest bacterial population was observed in intercropping of greengram-pea-greengram treatment (21.3 × 10⁶cfu/g).This was followed by intercropping of cowpea-pea-cowpea (18.4 × 10⁶ cfu/g). The maximum fungi population (14.8 × 10³cfu/g) was observed in cowpea-pea-cowpea treatment and maximum actinomycetes (8.4 × 10³ cfu/g) population was recorded in intercropping of greengram-pea-greengram treatment. Basal respiration was significantly more in treatments of intercropping systems. Among the treatments, intercropping of greengram-pea-greengram treatment (193 mg/kg of CO2-C) had more basal respiration rate during Kharif season in mango orchard. Similar trends were observed in citrus orchard.